mp2637 - monolithic power

MP2637 2.5A Single Cell Switch Mode Battery Charger

with Power Path Management (PPM) and 2.4A Boost Current with Trickle Timer

MP2637 Rev. 1.05 www.MonolithicPower.com 1 11/6/2020 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2021 MPS. All Rights Reserved.

The Future of Analog IC Technology

DESCRIPTION The MP2637 is a highly-integrated, flexible, switch-mode battery charger with system power path management, designed for single-cell Li-ion or Li-Polymer batteries used in a wide range of applications.

The MP2637 can operate in both charge mode and boost mode to allow full system and battery power management.

When input power is present, the device operates in charge mode. It automatically detects the battery voltage and charges the battery in three phases: trickle current, constant current and constant voltage. Other features include charge termination and auto-recharge. This device also integrates both input current limit and input voltage regulation in order to manage input power and meet the priority of the system power demand.

In the absence of an input source, the MP2637 switches to boost mode through the MODE pin to power the SYS pins from the battery. The OLIM pin programs the output current limit in boost mode. The MP2637 also allows for output short circuit protection to completely disconnect the battery from the load in the event of a short circuit fault. Normal operation will recover as soon as the short circuit fault is removed. The MP2637 provides full operating status indication to distinguish charge mode from boost mode.

To guarantee safe operation, the MP2637 limits the die temperature to a preset value of 120oC. Other safety features include input over-voltage protection, battery over-voltage protection, thermal shutdown, battery temperature monitoring, and a programmable timer to prevent prolonged charging of a dead battery.

FEATURES

Up to 16V Sustainable Input Voltage 4.5V-to-6V Operating Input Voltage Range Power Management function, Integrated

Input-Current Limit, Input Voltage Regulation

Up to 2.5A Programmable Charge Current Trickle-Charge Function Selectable 4.2V/ 4.35V Charge Voltage with

0.5% Accuracy Negative Temperature Coefficient Pin for

Battery Temperature Monitoring Programmable Timer Back-Up Protection Thermal Regulation and Thermal Shutdown Internal Battery Reverse Leakage Blocking Integrated Over Voltage Protection and

Over Current Protection for Pass-Through Path

Reverse Boost Operation Mode for System Power

Up to 2.4A Programmable Output Current Limit for Boost Mode

Integrated Short Circuit Protection and Output Over Voltage Protection for Boost Mode

Safety-Related Certification: o IEC 62368-1 AK Certification

APPLICATIONS Sub-Battery Applications Power-Bank Applications for Smart-Phone

Tablet and Other Portable Devices

All MPS parts are lead-free, halogen free, and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance.

“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc.

MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST


TYPICAL APPLICATION To 5V System

VIN

VCC

SW

BATT

FB

MODE

PWIN

SYS

Battery

CHG

EN

CIN

CBATT

C4*

TMR

NTC

PGND

OLIM

MP2637

ILIM

ISET

BOOST

ACOK

VBATT

REG

VSYS

VBBattery Voltage

ProgramGND: 4.35VHigh/Float: 4.2V

CSP

RS1

RISETCTMRRILIM

ROLIM*R1 R2

5V Input

AGND

R3R4

R5

L1*

C2CSYS*

ICHG

IBATT

R6

VCC

Q1 Q2 Q3

Q4

*Note: 1. ROLIM CANNOT be lower than 47.5kΩ. ROLIM is for the boost output current loop setting, and please refer to

the APPLICATION INFORMATION section for details. 2. CSYS should be put as close to the SYS pin and PGND as possible. At least 22μF is recommended, and

CSYS+C2 should not be less than 44μF, the ceramic is preferred and E-cap is not recommended. 3. VCC cap should not exceed 100nF. Recommend 47nF or 100nF. 4. Inductor should not exceed 2.2μH. Recommend 1.5μH or 2.2μH.



Table 1: Operation Mode

Power Source MODE EN

Operating Mode ACOK

__________

Q1,Q2 Q3 Q4 VIN PWIN

VIN> VBATT+300mV 0.8V<PWIN<1.15V X

Low Only Pass

Through Mode Low

On Off Off

High Charging Mode On SW SW

X PWIN<0.8V or PWIN >1.15V

High X Boost Discharge

Mode High Off SW SW

VIN <VBATT+300mV X

X PWIN<0.8V or PWIN >1.15V

Low X SYS Force-off

Mode High Off Off Off

VIN<2V X Low X Sleep Mode High Off Off Off

X=Don’t Care.

On = Fully Turn On

Off = Fully Off

SW = Switching



ORDERING INFORMATION Part Number* Package Top Marking

MP2637GR QFN-24 (4mm×4mm) See Below

* For Tape & Reel, add suffix –Z (e.g. MP2637GR–Z);

TOP MARKING

MPS: MPS prefix; Y: year code; WW: week code: MP2637: first six digits of the part number; LLLLLL: lot number;

PACKAGE REFERENCE



ABSOLUTE MAXIMUM RATINGS (1) VIN ................................................. –0.3V to 20V SYS ............................................... –0.3V to 6.5V SW …………….. .................................................

–0.3V (-2V for <20ns) to 6.5V (8.5V for <20ns) BATT ............................................. –0.3V to 6.5V

ACOK-----------------

, CHG-------------

, BOOST---------------------

................... –0.3V to 6.5V All Other Pins ................................ –0.3V to 6.5V Junction Temperature ............................... 150°C Lead Temperature .................................... 260°C

Continuous Power Dissipation (TA = +25°C) (2)

............................................................. 2.97W Junction Temperature ............................... 150°C Storage Temperature ............... –65°C to +150°C

Recommended Operating Conditions (3) Supply Voltage VVIN ............................ 4.5V to 6V Battery Voltage VBATT .................... 2.5V to 4.35V Operating Junction Temp. (TJ). −40°C to +125°C

Thermal Resistance (4) θJA θJC QFN-24 (4mm×4mm).............. 42 ........ 9 .... °C/W

Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the

maximum junction temperature TJ (MAX), the junction-to-ambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD (MAX) = (TJ

(MAX)-TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage.

3) The device is not guaranteed to function outside of its operating conditions.

4) Measured on JESD51-7, 4-layer PCB.



ELECTRICAL CHARACTERISTICS VIN = 5.0V, TA = 25°C, unless otherwise noted.

Parameter Symbol Condition Min Typ Max Units

IN to SYS NMOS ON Resistance RIN to SYS VCC=5V, 65 mΩ

High-side PMOS ON Resistance RH_DS VCC=5V, 30 mΩ

Low-side NMOS ON Resistance RL_DS VCC=5V, 30 mΩ

High-Side PMOS Peak Current Limit

IPEAK_HS CC Charge Mode/ Boost Mode

6.5 A

TC Charge Mode 3.2 A

Low-Side NMOS Peak Current Limit IPEAK_LS 6.3 A

Switching Frequency* fsw 490 600 700 kHz

VCC UVLO VCC_UVLO 2 2.2 2.4 V

VCC UVLO Hysteresis 100 mV

PWIN Lower Threshold VPWIN_L 0.75 0.8 0.85 V

Lower Threshold Hysteresis 50 mV

PWIN Upper Threshold VPWIN_H 1.1 1.15 1.2 V

Upper Threshold Hysteresis 50 mV

Charge Mode

Input Quiescent Current IIN EN = 5V, Battery Float 2.5 mA

EN = 0 1.5 mA

Input Current Limit IIN_LIMIT

RlLIM = 100k 400 450 500

mA RlLIM = 56k 720 810 900

RlLIM = 16.5k 2400 2700 3000

Input Over-Current Threshold IIN(OCP) 4.2 A

Input Over-Current Blanking Time(5) τINOCBLK 120 µs

Input Over-Current Recover Time(5) τINRECVR 100 ms

Terminal Battery Voltage VBATT_FULL

Connect VB to GND 4.328 4.35 4.372

V Leave VB floating or connect to logic HIGH

4.179 4.2 4.221

Recharge Threshold VRECH Connect to VB to GND 4.09 4.15 4.21

Leave VB floating or connect to logic HIGH

3.95 4.01 4.07 V

Recharge Threshold Hysteresis 200 mV

Battery Over Voltage Threshold As percentage of the VBATT_FULL

103.3% VBATT_

FULL

Constant Charge (CC) Current ICC

RS1 = 20mΩ, RISET = 120k 850 1000 1150

mA RS1 = 20mΩ, RISET = 60.4k 1725 1987 2250

RS1 = 20mΩ, RISET = 47.5k 2225 2525 2825

Trickle Charge Current ITC 125 250 mA

* Reserve 1200kHz Option



ELECTRICAL CHARACTERISTICS (continued) VIN = 5.0V, TA = 25°C, unless otherwise noted.


Trickle Charge Voltage Threshold VBATT_TC Connect to VB to GND 3.0 3.1 3.2

V Leave VB floating or connect to high logic

2.9 3 3.1

Trickle Charge Hysteresis 200 mV

Termination Charge Current IBF RS1 = 20mΩ, RISET=60.4k 2.5% 10% 17.5% ICC

RS1 = 20mΩ, RISET=47.5k 2.5% 10% 17.5% ICC

Input-Voltage-Regulation Reference

VREG 1.18 1.2 1.22 V

Boost Mode

SYS Voltage Range 4.2 6 V

Feedback Voltage 1.18 1.2 1.22 V

Feedback Input Current VFB=1V 200 nA

Boost SYS Over-Voltage Protection Threshold

VSYS(OVP)Threshold over VSYS to turn off the converter during boost mode

5.6 5.75 5.9 V

SYS Over Voltage Protection Threshold Hysteresis

VSYS falling from VSYS(OVP) 125 mV

Boost Quiescent Current ISYS = 0, MODE = 5V 1.4 mA

Programmable Boost Output Current Limit Accuracy

IOLIM RS1 = 20mΩ, ROLIM = 57.6k

1.875 2.083 2.290A

RS1 = 20mΩ, ROLIM = 51k 2.1

SYS Over-Current Blanking Time(5)

τSYSOCBLK 120 µs

SYS Over-Current Recover Time(5)

τSYSRECVR 1 ms

Weak-Battery Threshold VBATT(LOW)During boosting 2.5 V

Before Boost starts 2.9 3.05 V

Sleep Mode

Battery Leakage Current ILEAKAGE VBATT = 4.2V, SYS Float, VIN = 0V, MODE = 0V

15 30 μA

Indication and Logic

ACOK----------------

, CHG-------------

, BOOST-------------------

pin output low voltage

Sinking 1.5mA 400 mV

ACOK----------------

, CHG-------------

, BOOST-------------------

pin leakage current

Connected to 5V 1 μA

NTC and Time-out Fault Blinking Frequency(5)

CTMR = 0.1μF, ICHG = 1A 12.5 Hz

EN Input Logic Low Voltage 0.4 V

EN Input High Voltage 1.4 V

Mode Input Logic Low Voltage 0.4 V

Mode Input Logic High Voltage 1.4 V



ELECTRICAL CHARACTERISTICS (continued) VIN = 5.0V, TA = 25°C, unless otherwise noted.


Protection

Trickle Charge Time CTMR=0.1µF, remains in TC Mode, ITC= 100mA test mode

26 Min

Total Charge Time CTMR=0.1µF, ICHG= 1A 336 Min

NTC Low Temp, Rising Threshold RNTC=NCP18XH103(0ºC)

65.6% 66.6% 67.6%

VSYS

NTC Low Temp, Rising Threshold Hysteresis

1%

NTC High Temp, Rising Threshold

RNTC=NCP18XH103(50ºC)

34% 35% 36%

NTC High Temp, Rising Threshold Hysteresis

1%

Charging Current Foldback Threshold(5)

Charge Mode 120 °C

Thermal Shutdown Threshold(5) 150 °C

Notes: 5) Guaranteed by design.



TYPICAL CHARACTERISTICS CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator, unless otherwise noted.

VO

LTA

GE

(V

)

INPUT VOLTAGE (V)

I OLI

M (

A)

ROLIM (K)

INP

UT

CU

RR

EN

T L

IMIT

(A

)

Programmable Input Current Limit, Charge ModeVIN=5V, VBATT_FULL=4.2V,

VBATT=3.7V, FSW=600k

Battery Leakage Current, Sleep ModeMODE=low

VCC @ Charge Mode VCC @ Boost ModeProgrammable Output Current Limit, Boost ModeFSW=600k

SYS_OVP vs. TemperatureSYS_OVP=6V

Output Current Limit 2.2A vs. TemperatureROLIM=54.4k

Battery Current in Sleep Mode vs. Temperature

VBATT (V)

BATTERY VOLTAGE (V)

SY

S_O

VP

_R (

V)

I CH

G (A

)

RISET (K)

Programmable Charge Current, Charge ModeVIN=5V, VBATT_FULL=4.2V,

VBATT=3.7V, FSW=600k

0

0.5

1

1.5

2

2.5

3

3.5

20 70 120 170 220 2700

0.5

1

1.5

2

2.5

3

10 30 50 70 900

5

10

15

20

25

30

2.81 3.31 3.81 4.31 4.81

0.4

0.8

1.2

1.6

2

2.4

2.8

30 60 90 120 150 180

VBATT=3V

VBATT=3.7V

VBATT=4.35V

VBATT=4.5V

0

1

2

3

4

5

6

7

8

2 3 4 5 6 70

1

2

3

4

5

6

7

1.5 2.5 3.5 4.5 5.5

VO

LTA

GE

(V

)

0

4

8

12

16

20

-50 0 50 100 -50 0 50 1005.972

5.976

5.98

5.984

5.988

5.992

2.16

2.2

2.24

2.28

2.32

2.36

-60 -30 0 30 60 90 120 150

OLI

M_5

4.4K

(A

)



TYPICAL CHARACTERISTICS (continued) CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator, unless otherwise noted.

VB

AT

T (

V)

Battery Full Voltage vs. TemperatureVBATT_FULL = 4.35V

CC Chagre Current vs. TemperatureRISET=47.5k

Battery OVP Threshold vs.TemperatureVBATT_FULL = 4.2V

IN_SYS_N_Rdson vs. Temperature

Battery OVP Threshold vs.TemperatureVBATT_FULL = 4.35V

HS_Rdson vs. TemperatureLS_Rdson vs. Temperature

VB

AT

T (V

)

Battery Full Voltage vs. TemperatureVBATT_FULL = 4.2V

4.188

4.19

4.192

4.194

4.196

4.198

-50 0 50 100

-50 0 50 100 -50 0 50 100

-50 0 50 100 -50 0 50 100

-50 0 50 100

-50 0 50 100 -50 0 50 1004.338

4.34

4.342

4.344

4.346

4.348

2.3

2.4

2.5

2.6

2.7

I_C

C_4

7.5K

(A)

103.1

103.2

103.3

103.4

103.5

103.6

103.1

103.2

103.3

103.4

103.5

103.6

30

50

70

90

20

24

28

32

36

40

20

24

28

32



TYPICAL PERFORMANCE CHARACTERISTICS For Charge Mode: VIN = 5V, ICHG = 2.5A, LIN_LIM = 2.7A, ISYS = 0A For Boost Mode: VBATT = 3.7V, VSYS_SET = 5V, IOLIM = 2.1A CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator, unless otherwise noted.

TC Charge Steady StateVBATT_FULL=4.2V, VBATT =2V, fSW=600KHz

CC Charge Steady StateVBATT_FULL=4.2V, VBATT =3.7V, fSW=600KHz

CV Charge Steady StateVBATT_FULL=4.2V, VBATT =4.2V, fSW=600KHz

VIN1V/div.

VBATT1V/div.

VBATT1V/div.

CHG2V/div.

VIN1V/div.

IBATT1A/div.

VIN1V/div.

VBATT100mV/div.

CHG2V/div.

IBATT1A/div.

VSW1V/div.

VBATT200mV/div.

CHG2V/div.

IL100mA/div.

VSW2V/div.

IL500mA/div.

VBATT2V/div.

VIN1V/div.

VSW2V/div.

IL1A/div.

VBATT1V/div.

VIN1V/div.

VSW2V/div.

IL500mA/div.

Battery Charge CurveVBATT_FULL=4.2V

Auto RechargeVBATT_FULL=4.2V

Battery Float Steady StateVBATT_FULL=4.2V

IBATT (A)

Constant Voltage Charge EfficiencyVBATT_FULL=4.2V, VBATT =4.2V,

fSW=600kHz

90

92

94

96

98

0 0 .5 1 1 .5 2 2 .5 3VBATT (V)

Constant Current Charge EfficiencyVBATT_FULL=4.2V, VBATT =0.5-4.2V,

fSW=600kHz

60

70

80

90

100

2.8 3 3.2 3.4 3.6 3.8 4 4.2 4.4

VIN=5.8VVIN=5.4V

VIN=5V

VIN=5.4V

VIN=5.8V

VIN=5V



TYPICAL PERFORMANCE CHARACTERISTICS (continued) For Charge Mode: VIN = 5V, ICHG = 2.5A, LIN_LIM = 2.7A, ISYS = 0A For Boost Mode: VBATT = 3.7V, VSYS_SET = 5V, IOLIM = 2.1A CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator, unless otherwise noted.




VBATT1V/div.

SW2V/div.

VSYS1V/div.

IL500mA/div.

VBATT1V/div.

SW2V/div.

VSYS1V/div.

IL200mA/div.

VBATT1V/div.

VSYS1V/div.

SW2V/div.

ISYS1A/div.

VBATT1V/div.

VSYS1V/div.

SW2V/div.

ISYS1A/div.

IL500mA/div.

VSYS1V/div.

MODE5V/div.

SW2V/div.

ISYS1A/div.

VSYS1V/div.

MODE5V/div.

SW2V/div.

ISYS1A/div.

ISYS1A/div.

VSYS1V/div.

MODE5V/div.

SW2V/div.

IL200mA/div.

VSYS1V/div.

MODE5V/div.

SW2V/div.

Power On, Boost ModeVSYS_SET=5V, VBATT=3.7V, No SYS Load

Power Off, Boost ModeVSYS_SET=5V, VBATT=3.7V, No SYS Load

Mode On, Boost ModeVSYS_SET=5V, VBATT=3.7V, No SYS Load

Mode Off, Boost ModeVSYS_SET=5V, VBATT=3.7V, No SYS Load

SYS Output Current LimitVSYS_SET=5V, VBATT=3.7V, IOLIM_SET=2.5A

VSYS1V/div.

VBATT2V/div.



PIN FUCTIONS Pin # Name Description

1, 23, 24 PGND Power Ground.

2 CHG------------

Charge Completion Indicator. Logic LOW indicates charge mode. This is an open drain pin during charge complete or suspended

3 BOOST-------------------

Boost Mode indicator. Logic LOW indicates boost mode in operation. This is an open drain pin during charge mode or sleep mode operation.

4 CSP Battery Charge Current Sense Positive Input. 5 BATT Positive Battery Terminal / Battery Charge Current Sense Negative Input. 6 AGND Analog Ground

7 OLIM Programmable Output-Current Limit for boost mode. Connect an external resistor to GND to program the system current in boost mode. The ROLIM CANNOT be lower than 47.5kΩ.

8 ISET Programmable Charge Current Pin. Connect an external resistor to GND to program the charge current.

9 NTC Negative Temperature Coefficient (NTC) Thermistor. 10 FB System voltage feedback input.

11 ACOK----------------

Valid Input Supply Indicator. Logic LOW on this pin indicates the presence of a valid power supply.

12 REG

Input Voltage Feedback for input voltage regulation loop. Connect to tap of an external resistor divider from VIN to GND to program the input voltage regulation. Once the voltage at REG pin drops to the inner threshold, the charge current is reduced to maintain the input voltage at the regulation value.

13 TMR Oscillator Period Timer. Connect a timing capacitor between this pin and GND to set the oscillator period. Short to GND to disable the Timer function.

14 PWIN Input pin to detect the presence of valid input power. Pulling this pin to GND will turn off the IN-to-SYS pass through MOSFET

15 ILIM Input Current Set. Connect to GND with an external resistor to program input current limit in charge mode.

16 VCC Internal Circuit Power Supply. Bypass this pin to GND with a ceramic capacitor not higher than 100nF. This pin CANNOT carry external load higher than 5mA.

17 VB Programmable Battery-Full Voltage. Leave floating or connect to logic HIGH for 4.2V, while connect to GND for 4.35V.

18 EN Charge Control Input. Logic HIGH enables charging. Logic LOW disables charging. Active

only when ACOK__________

is low (input power is OK).

19 MODE Mode Select. Logic HIGH→boost mode. Logic LOW→sleep mode. Active only when

ACOK__________

is HIGH (input power is not available).

20 VIN Adapter Input. Place a bypass capacitor close to this pin to prevent large input voltage spikes.

21 SYS System Output. A minimum of 22uF ceramic cap is required to be placed as close as possible to the SYS and PGND pins. Total capacitance should not be lower than 44uF

22 SW Switch Output Node. It is recommended not to place Via's on the SW plane during PCB layout



BLOCK DIAGRAM

0.8V

1.15V

BATT+300mV

VCC

PWIN

VIN

SYS FB

A1

A2

Control Logic&Mode Selection

TMR

SW

VCC

Driver

VBATT

GMIMIN

GMV

VBATT_Ref

ICHG_Ref

PWM Controller

Current Setting

Mode Control

GMINI

IIN_Ref

GMINV

VREG_Ref

REG

VBATT

MODEGMT

TRef

TJ

NTC

VCC VCC

Indication&Timer

ACOK

CHG

BOOST

EN

PWM Signal

HSMOS

LSMOS

ISET

ILIM

OLIM

AGND

BATT

Charge Pump

ACOK

VB

K1*ICHG

K2*IIN

CSPCurrent Sense

K1*ICHG

Thermal Shutdown

VBATT

Buffer

Q1 Q2

PGND

Figure 1: Functional Block Diagram in Charge Mode



0.8V

1.15V

BATT+300mV

VCC

PWIN

VIN

SYS FB

A1

A2

Control Logic&Mode Selection

TMR

SW

VCC

Driver

VBATT

GMV

PWM Controller

Current Setting

Mode Control

GMINI

REG

MODE

NTC

Indication&Timer

ACOK

CHG

BOOST

EN

PWM Signal

HSMOS

LSMOS

ISET

ILIM

OLIM

PGND

AGND

BATTCharge Pump

ACOK

VB

CSP

VBATT

VSYS_Ref

VFB

K3*ISYS

IOLIM_Ref

Integration

To Current Setting

Thermal Shutdown

Q1 Q2

Figure 2: Functional Block Diagram in Boost Mode



OPERATION FLOW CHART

POR

VCC<VCC_UVLO

VPWIN_L<VPWIN<VPWIN_H

&VIN>VBATT+300mV

Yes

No

MODE High?

No

No

Boost Mode/BOOST Low

Yes

/ACOK is Low, System Powered By IN

Yes

EN High?

No

Charge Mode/CHG Low

Yes

Sleep Mode

Figure 3: Mode Selection Flow Chart



OPERATION FLOW CHART (continued)

Figure 4: Normal Operation and Fault Protection in Charge Mode



OPERATION FLOW CHART (continued)

Normal Operation

Power Path Management

IIN hit the IIN_LIMIT?

Charge Current Decrease

ICHG =0?

SYS Output Current Increase

No

Yes

No

Yes

VPWIN touch the VREG?

Yes

No

IIN exceeds IIN(OCP)?No

IN to SYS MOSFET turns Off

Yes

TINOCBLK reaches?

No

TINRECVR reaches?

Regulate the IIN at IIN(OCP)

Yes

IIN >7A?

No

No

Yes

Yes

Figure 5: Power-path Management in Charge Mode



OPERATION FLOW CHART (continued) Boost Mode

/BOOST Low

VBATT >2.9V?

No

Yes

Normal Boost Operation

Mode High?

No

Yes

VBATT<2.5V?

No

Boost Turns Off

Yes

Normal Boost Operation

ISYS > IOLIM?

Output current loop works, VSYS decreases

VSYS < VBATT?

Yes

VSYS < 2V?

Yes

Yes

IL hits the current limit

No

Boost Shutdown

TSYSRECVR

Reaches?

Down mode

No

TSYSBLK Reaches?

No

No

Yes

No

Yes Yes

Figure 6: Operation Flow Chart in Boost Mode



START UP TIME FLOW IN CHARGE MODE Condition: EN = 5V, Mode = 0V, /ACOK and /CHG are always pulled up to an external 5V.

VIN

SS

ForceCharge

Auto-recharge threshold

IBF

Comparator

Auto-recharge

VSYS

ACOK

Band Gap

0V

0V

VPWIN > 0.8V&

VIN > VBATT+ 300mV

VSYS > VBATT + 50mV

0V

5V

CHG0V

5V

0A

ICC

10%ICC

Battery Voltage

VBATT_FULL

150μs

Assume vBATT > VBATT_TC

150μs

0V

5V

Mode

EN

VCC

2.2V

Charge Current

VCC follows VIN

0V

400μs 400μs

Figure 7: Input Power Start-Up Time Flow in Charge Mode



START UP TIME FLOW IN CHARGE MODE Condition: EN = 5V, Mode = 0V, /ACOK and /CHG are always pulled up to an external 5V.

VIN

SS

ForceCharge

IBF

Comparator

Auto-recharge

VSYS

ACOK

Band Gap

0V

0V

0V

5V

CHG0V

5V

0A

ICC

10%ICC

Battery Voltage

VBATT_FULL

150μs

Assume vBATT > VBATT_TC

150μs

0V

5V

Mode

EN

VCC

2.2V

Charge Current

0V

400μs 400μs

150μs

400μs

Figure 8: EN Start-Up Time Flow in Charge Mode



START UP TIME FLOW IN BOOST MODE Condition: VIN = 0V, Mode = 5V, /Boost is always pulled up to an external constant 5V.

MODE

Boost SS

VCC

Band Gap

VSYS

VBATT

2.2V

BOOST

0V2.9V

VSYS>VBATT+300mV0V

0V

5V

Down Mode

2.5V

0V

VCC follows VBATT

VCC follows VSYS

1.2ms

Figure 9: Battery Power Start-Up Time Flow in Boost Mode



START UP TIME FLOW IN BOOST MODE Condition: VIN = 0V, /Boost is always pulled up to an external constant 5V.

MODE

Boost SS

VCC

Band Gap

VSYS

VBATT

2.2V

BOOST

2.9V

VSYS>VBATT+300mV0V

0V

5V

Down Mode

0V

5V

0V

5V

VCC follows VBATT

VCC follows VSYS

1.2ms

Figure 10: Mode Start-Up Time Flow in Boost Mode



OPERATIONINTRODUCTION The MP2637 is a highly-integrated, flexible, switch-mode battery charger with system power path management, designed for single-cell Li-ion or Li-Polymer batteries used in a wide range of applications. Depending on the status of the Input, the MP2637 can operate in three different modes: Charge Mode; Boost Mode; Sleep Mode.

In charge mode the MP2637 can work with a single cell Li-ion or Li-polymer battery. In boost mode the MP2637 boosts the battery voltage to VSYS_SET to power higher voltage system rails. In sleep mode both charging and boost operations are disabled and the device enters a power saving mode to help reduce the overall power consumption. The MP2637 monitors VIN to allow smooth transition between different modes of operation.

CHARGE MODE OPERATION Charge Cycle (Trickle ChargeCC ChargeCV Charge) In charge mode, the MP2637 has five control loops to regulate the input current, input voltage, charge current, charge voltage, and device junction temperature. The MP2637 charges the battery in three phases: trickle current (TC), constant current (CC), and constant voltage (CV). While charge operation is enabled, all five loops are active but only one determines the IC behavior. A typical battery charge profile is depicted in Figure11 (a). The charger stays in TC charge mode until the battery voltage reaches a TC-to-CC threshold. Otherwise the charger enters CC charge mode. When the battery voltage rises to the CV-mode threshold, the charger operates in constant voltage mode. Figure (b) shows a typical charge profile when the input-current-limit loop dominates during the CC charge mode, and in this case the charger maximizes the charging current due to the switching-mode charging solution, resulting in faster charging than a traditional linear solution.

Trickle charge

TC>>>CC Threshold

CC>>>CVThreshold

CC charge CV charge

ICHGVBAT

Charge Full

Trickle Charge Current

Constant Charge Current

a) Without input current limit

Trickle charge

TC>>>CC Threshold

CC>>>CVThreshold

CC charge CV charge

ICHG

VBAT

Charge Full

Trickle Charge Current

Input Current Limit

ConstantCharge Current

b) With input current limit

Figure 11: Typical Battery Charge Profile

Auto-recharge Once the battery charge cycle is completed, the charger remains off. During this time, the system load may consume battery power, or the battery may self discharge. To ensure the battery will not go into depletion, a new charge cycle automatically begins when the battery voltage falls below the auto-recharge threshold and the input power is present. The timer is reset when the auto-recharge cycle begins.

During the off state after the battery is fully charged, if the input power re-starts or the EN signal refreshes, the charge cycle will start and the timer will reset no matter what the battery voltage is.

Battery Over-Voltage Protection The MP2637 has battery over-voltage protection. If the battery voltage exceeds the battery over-voltage threshold, (103.3% of the battery-full voltage), charging is disabled. Under this condition, an internal 5kΩ dummy load draws a



current from the BATT pin to decrease the battery voltage and protect the battery.

Timer Operation in Charge Mode The MP2637 uses an internal timer to terminate the charging. The timer remains active during the charging process. An external capacitor between TMR and GND programs the charge cycle duration.

If charging remains in TC mode beyond the trickle-charge time, τTRICKLE_TMR, charging will terminate. The following equation determines the length of the trickle-charge period:

4TMR

TC _ TMRTC

4.5 10 1.6(V) C ( F)(s)

1.25 I (A) RS1(m ) 2( A)

(1)

The maximum total charge time is:

6TMR

TOTAL _ TMRCHG

3.4 10 1.6(V) C ( F)(s)

1.25 I (A) RS1(m ) 2( A)

(2)

Negative Temperature Coefficient (NTC) Input for Battery Temperature Monitoring The MP2637 has a built-in NTC resistance window comparator, which allows the MP2637 to monitor the battery temperature via the battery-integrated thermistor. Connect an appropriate resistor from VSYS to the NTC pin and connect the thermistor from the NTC pin to GND. The resistor divider determines the NTC voltage depending on the battery temperature. If the NTC voltage falls outside of the NTC window, the MP2637 stops charging. The charger will then restart if the temperature goes back into NTC window range. Please refer to Application Information section for the appropriate resistance selection.

Input Current Limiting in Charge Mode The MP2637 has a dedicated pin used to program the input current limit. The current at ILIM is a fraction of the input current; the voltage at ILIM indicates the average input current of the switching regulator as determined by the resistor value between ILIM and GND. As the input current approaches the programmed input current limit, charge current is reduced to allow priority to system power.

Use the following equation to determine the input current limit threshold.

ILIM

ILIM

45(k )I (A)

R (k )

(3)

Input Voltage Regulation in Charge Mode In charge mode, if the input power source is not sufficient to support both the charge current and system load current, the input voltage will decrease. As the input voltage approaches the programmed input voltage regulation value, charge current is reduced to allow priority of system power and maintain proper regulation of the input voltage.

The input voltage can be regulated by a resistor divider from IN pin to REG pin to AGND according to the following equation:

REG IN_R

R5V V (V)

R3 R5

(4)

where the VREG is the internal voltage reference, 1.2V, and the VIN_R is the desired regulation voltage.

Integrated Over Current Protection and Over Voltage Protection for Pass-through Path The MP2637 has an integrated IN to SYS pass-through path to allow direct connection of the input voltage to the system even if charging is disabled. Based on the above, the MP2637 continuously monitors both input current and voltage. In the event of an OCP or OVP charge current will be reduced to ensure priority of the system power requirements.

In addition, the MP2637 also features input over current and voltage protection for the IN to SYS pass-through path.

Input over-current protection (OCP):

When the total input current exceeds 4.2A, Q2 (Fig 12) is controlled linearly to regulate the current. If the current continues to exceeds 4.2A after a 120µs blanking time, Q2 will be turn off. In the event of input current exceeding 7A Q2 will be turned off almost instantaneously and without any blanking time, this to protect both Q1 and Q2.

Input over-voltage protection (OVP):

The MP2637 uses the PWIN pin to sense the status of input voltage. When the voltage at the PWIN pin is lower than 0.8V or higher than 1.15V, an invalid input power source is detected by the MP2637. At this time the IN to SYS pass-through path will be turned off. An OVP threshold can be programmed via PWIN pin to prevent an over



voltage event happening at SYS side when plugging in a wrong adapter.

IN

SYS

Charge Pump

Q1 Q2

Figure12: Integrated Pass-through Path

Charge Current Setting The external sense resistors, RS1 and RISET, program the battery charge current, ICHG. Select RISET based on RS1:

CHGISET

2400I (A)

R (k ) RS1(m )

(5)

Battery Short Protection The MP2637 has two current limit thresholds. CC and CV modes have a peak current limit threshold of 6.5A, while TC mode has a current limit threshold of 3.2A. Therefore, the current limit threshold decreases to 3.2A when the battery voltage drops below the TC threshold. Moreover, the switching frequency also decreases when the BATT voltage drops to 40% of the charge-full voltage.

Thermal Foldback Function The MP2637 implements thermal protection to prevent thermal damage to the IC and the surrounding components. An internal thermal sense and feedback loop automatically decreases the programmed charge current when the die temperature reaches 120°C. This function is called the charge-current-thermal foldback. Not only this function protects against thermal damage, it can also set the charge current based on requirements rather than worst-case conditions while ensuring safe operation. Furthermore, the part includes thermal shutdown protection where the ceases charging if the

junction temperature rises to 150°C.

Non-sync Operation Mode During charging mode, the MP2637 continuously monitors the total input current flowing from IN pin to SYS pin. When the input current is lower than 170mA, the low side switch operates as a non-synchronous MOSFET.

Constant-Off-Time Control for Large Duty Charging Operation The MP2637 has a built-in 600kHz frequency oscillator for the switching frequency. Unlike a traditional fixed frequency, the MP2637 features a constant off time control to support constant-current charge even when the input voltage is very close to battery voltage. As shown in the Figure 13, the MP2637 continuously compares the high-side FET sense current with comp level, if the sense current doesn’t reach the comp level within the original switching period, the next clock will be delayed until the sense current reaches the comp level. As a result the duty cycle is able to be extended as large as possible.

Full Operation Indication The MP2637 integrates indicators for the following conditions as shown in Table2. The blinking frequency is:

BlinkingTMR

1( A)F

0.8 C ( F)

(6)

Table 2: Indicator for Each Operation Mode

Operation ACOK----------------

CHG------------

BOOST-------------------

Charge Mode

In Charging

Low

Low

High

End of Charge, Charging disabled, Battery OVP

High

NTC Fault, Timer Out

Blinking

Boost Mode High High Low

Sleep Mode High High High



Figure 13: Constant-Off-Time Operation Profile



BOOST MODE OPERATION Low-Voltage Start-Up The minimum battery voltage required to start up the circuit in boost mode is 2.9V. Initially, when VSYS < VBATT, the MP2637 works in down mode. In this mode, the synchronous P-MOSFET stops switching and its gate connects to VBATT statically. The P-MOSFET stays off as long as the voltage across the parasitic CDS (VSW) is lower than VBATT. When the voltage across CDS exceeds VBATT, the synchronous P-MOSFET enters linear mode allowing the inductor current to decrease and flowing into the SYS pin. Once VSYS exceeds VBATT, the P-MOSFET gate is released and normal closed-loop PWM operation is initiated. In boost mode, the battery voltage can drop to as low as 2.5V without affecting circuit operation.

SYS Disconnect and Inrush Limiting The MP2637 allows for true output disconnect by eliminating body diode conduction of the internal P-MOSFET rectifier. VSYS can go to 0V during shutdown, drawing no current from the input source. It also allows for inrush current limiting at start-up, minimizing surge currents from the input supply. To optimize the benefits of output disconnect, avoid connecting an external Schottky diode between the SW and SYS pins.

Board layout is extremely critical to minimize voltage overshoot at the SW pin due to stray inductance. Keep the output filter capacitor as close as possible to the SYS pin and use very low ESR/ESL ceramic capacitors tied to a good ground plane.

Boost Output Voltage Setting In boost mode, the MP2637 programs the output voltage via the external resistor divider at FB pin, and provides built-in output over-voltage protection (OVP) to protect the device and other components against damage when VSYS goes beyond 6V. Once the output over voltage occurs, the MP2637 turns off the boost converter. When the voltage on VSYS drops to a normal level, the

boost converter restarts again as long as the MODE pin remains in active status.

Boost Output Current Limiting The MP2637 integrates a programmable output current limit function in boost mode. If the boost output current exceeds this programmable limit, the output current will be limited at this level and the SYS voltage will start to drop down. The OLIM pin programs the current limit threshold up to 2.4A as per the following equation:

OLIMOLIM

2400I (A)

R (k ) RS1(m )

(7)

SYS Output Over Current Protection The MP2637 integrates three-phase output over-current protection.

Phase one (boost mode output current limit): when the output current exceeds the programmed output current limit, the output constant current loop controls the output current, the output current remains at its limit of IOLIM, and VSYS decreases.

Phase two (down mode): when VSYS drops below VBATT+100mV and the output current loop remains in control, the boost converter enters down mode and shutdown after a 120μs blanking time.

Phase three (short circuit mode): when VSYS drops below 3.75V (will be 2V during boost soft start), the boost converter shuts down immediately once the inductor current hits the fold-back peak current limit of the low side N-MOSFET. The boost converter can also recover automatically after a 1ms deglitch period.

Thermal Shutdown Protection The thermal shutdown protection is also active in boost mode. Once the junction temperature rises higher than 150°C, the MP2637 enters thermal shutdown. It will not resume normal operation until the junction temperature drops below 120°C



APPLICATION INFORMATION

COMPONENT SELECTION

Setting the Charge Current in Charge Mode

In charge mode, both the external sense resistor, RS1, and the resistor RISET connect to the ISET pin to set the charge current (ICHG) of the MP2637 (see the Typical Application circuit). Given ICHG and RS1, RISET can be calculated as:

ISETCHG

2400R (k )

I (A) RS1(m )

(8)

For example, for ICHG=2.5A, and RS1=20mΩ, thus: RISET=48kΩ.

Setting the Input Current Limiting in Charge Mode

In charge mode, connect a resistor from the ILIM pin to AGND to program the input current limit. The relationship between the input current limit and setting resistor is as following:

ILIMIN _LIM

45R (k )

I (A) (9)

where RILIM must exceed 16.5kΩ, so that IIN_LIM is in the range of 0A to 2.7A.

For most applications, use RILIM = 50kΩ (IUSB_LIM=900mA) for USB3.0 mode, and use RILIM = 90kΩ (IUSB_LIM=500mA) for USB2.0 mode.

Setting the Input Voltage Range for Different Operation Modes

A resistive voltage divider from the input to PWIN pin determines the operating mode of MP2637.

PWIN IN

R6V V (V)

R4 R6

(10)

If the voltage on PWIN is between 0.8V and 1.15V, the MP2637 works in the charge mode. While the voltage on the PWIN pin is not in the range of 0.8V to 1.15V and VIN > 2V, the MP2637 works in the boost mode (see Table 1)).

For a wide operating range, use a maximum input voltage of 6V as the upper threshold for a voltage ratio of:

PWIN

IN

V 1.15 R6

V 6 R4 R6

(11)

With the given R6, R4 is then:

IN PWIN

PWIN

V VR4 R6

V

(12)

For a typical application, start with R6=5.1kΩ, R4 is 21.5kΩ.

Setting the Input Voltage Regulation in Charge Mode In charge mode, connect a resistor divider from the IN pin to AGND with tapped to REG pin to program the input voltage regulation.

IN_R REG

R3 R5V V (V)

R5

(13)

With the given R5, R3 is:

IN_R REG

REG

V VR3 R5(V)

V

(14)

For a preset input voltage regulation value, say 4.75V, start with R5=5.1kΩ, R3 is 15kΩ.

NTC Function in Charge Mode Figure 14 shows that an internal resistor divider sets the low temperature threshold (VTL) and high temperature threshold (VTH) at 66.6%·VSYS and 35%·VSYS, respectively. For a given NTC thermistor, select an appropriate RT1 and RT2 to set the NTC window.

%6.66

TLNTC_ColdT2T1

NTC_ColdT2

SYS

TL

//RRR

//RR

V

V (15)

%35

THNTC_HotT2T1

NTC_HotT2

SYS

TH

//RRR

//RR

V

V (16)

Where RNTC_Hot is the value of the NTC resistor at the upper bound of its operating temperature range, and RNTC_Cold is its lower bound.

The two resistors, RT1 and RT2, independently determine the upper and lower temperature limits. This flexibility allows the MP2637 to operate with most NTC resistors for different temperature range requirements. Calculate RT1 and RT2 as follows:



NTC_Hot NTC_ColdT1

NTC_Cold NTC_Hot

R R (TL TH)R

TH TL (R R )

(17)

NTC_Cold NTC_HotT2

NTC_Cold NTC_Hot

(TL TH) R RR

(1 TL) TH R -(1-TH) TL R

(18)

For example, the NCP18XH103 thermistor has the following electrical characteristic:

At 0°C, RNTC_Cold = 27.445kΩ;

At 50°C, RNTC_Hot = 4.1601kΩ.

Based on equation (17) and equation (18), RT1=6.65kΩ and RT2 = 25.63kΩ are suitable for an NTC window between 0°C and 50°C. Chose approximate values: e.g., RT1=6.65kΩ and RT2=25.5kΩ.

If no external NTC is available, connect RT1 and RT2 to keep the voltage on the NTC pin within the valid NTC window: e.g., RT1 = RT2 = 10kΩ.

Figure 14: NTC Function Block

For convenience, an NTC thermistor design spreadsheet is also provided, please inquire if necessary.

Setting the System Voltage in Boost Mode In the boost mode, the system voltage can be regulated to the value customer required between 4.2V to 6V by the resistor divider at FB pin as R1 and R2 in the typical application circuit.

SYS

R1 R2V 1.2V

R2

(19)

where 1.2V is the voltage reference of SYS. With a typical value for R2, 10kΩ, R1 can be determined by:

SYSV 1.2VR1 R2 (V)

1.2V

(20)

For example, for a 5V system voltage, R2 is 10kΩ, and R1 is 31.6kΩ.

Setting the Output Current Limit in Boost Mode In boost mode, connect a resistor from the OLIM pin to AGND to program the output current limit. The relationship between the output current limit and setting resistor is as follows:

OLIMOLIM

2400I (A)

R (k ) RS1(m )

(21)

The output current limit of the boost can be programmed up to 2.1A (min). Considering 10% output current limit accuracy, typical 2.3A output current limit is required. According to the above equation, given 20mΩ sense resistor, 52k ROLIM will get 2.3A output current limit.

For safety operation, ROLIM CANNOT be lower than 47.5kΩ

Selecting the Inductor Inductor selection trades off between cost, size, and efficiency. A lower inductance value corresponds with smaller size, but results in higher current ripple, higher magnetic hysteretic losses, and higher output capacitances. However, a higher inductance value benefits from lower ripple current and smaller output filter capacitors, but results in higher inductor DC resistance (DCR) loss.

Choose an inductor that does not saturate under the worst-case load condition.

1. In Charge Mode

When MP2637 works in charge mode (as a Buck Converter), estimate the required inductance as:

IN BATT BATT

L _ MAX IN SW

V V VL

I V f

(22)

where VIN, VBATT, and fS are the typical input voltage, the CC charge threshold, and the switching frequency, respectively. ∆IL_MAX is the maximum peak-to-peak inductor current, which is usually designed at 30%-40% of the CC charge current.

With a typical 5V input voltage, 35% inductor current ripple at the corner point between trickle charge and CC charge (VBATT=3V, Ichg=2.5A), the inductance 2.2μH.

2. In Boost Mode



When the MP2637 is in Boost mode (as a Boost converter), the required inductance value is calculated as:

BATT SYS BATT

SYS SW L _ MAX

V (V V )L

V f I

(23)

L _ MAX BATT(MAX)I (30% 40%) I (24)

SYS SYSBATT(MAX)

BATT

V II

V

(25)

Where VBATT is the minimum battery voltage, fSW

is the switching frequency, and ∆IL_MAX is the peak-to-peak inductor ripple current, which is approximately 30% of the maximum battery current IBATT(MAX), ISYS(MAX) is the system current and η is the efficiency.

In the worst case where the battery voltage is 3V, a 30% inductor current ripple, and a typical system voltage (VSYS=5V), the inductance is 1.5µH when the efficiency is 90%.

For best results, use an inductor with an inductance of 2.2uH with a DC current rating that is not lower than the peak current of MOSFET. For higher efficiency, minimize the inductor’s DC resistance.

Selecting the Input Capacitor CIN The input capacitor CIN reduces both the surge current drawn from the input and the switching noise from the device. The input capacitor impedance at the switching frequency should be less than the input source impedance to prevent high-frequency-switching current from passing to the input. For best results, use ceramic capacitors with X7R dielectrics because of their low ESR and small temperature coefficients. For most applications, a 22µF capacitor will suffice.

Selecting the System Capacitor CSYS Select CSYS based on the demand of the system current ripple.

1. Charge Mode

The capacitor CSYS acts as the input capacitor of the buck converter in charge mode. The input current ripple is:

TC IN _ MAX TC

RMS _ MAX SYS _ MAXIN _ MAX

V (V V )I I

V

(26)

2. Boost Mode

The capacitor, CSYS, is the output capacitor of boost converter. CSYS keeps the system voltage ripple small and ensures feedback loop stability. The system current ripple is given by:

TC SYS _ MAX TC

RMS _ MAX SYS _ MAXSYS _ MAX

V (V V )I I

V

(27)

Since the input voltage is passes to the system directly, VIN_MAX=VSYS_MAX, both charge mode and boost mode have the same system current ripple.

For ICC_MAX=2A, VTC=3V, VIN_MAX=6V, the maximum ripple current is 1.25A. Select the system capacitors base on the ripple-current temperature rise not exceeding 10°C. For best results, use ceramic capacitors with X7R dielectrics with low ESR and small temperature coefficients. For most applications, use three 22µF capacitors.

Selecting the Battery Capacitor CBATT

CBATT is in parallel with the battery to absorb the high-frequency switching ripple current.

1. Charge Mode

The capacitor CBATT is the output capacitor of the buck converter. The output voltage ripple is then:

BATT SYSBATTBATT 2

BATT BATT SW

1 V / VVr

V 8 C f L

(28)

2. Boost Mode

The capacitor CBATT is the input capacitor of the boost converter. The input voltage ripple is the same as the output voltage ripple from equation (28)

Both charge mode and boost mode have the same battery voltage ripple. The capacitor CBATT can be calculated as:

TC SYS _ MAXBATT 2

BATT _ MAX SW

1 V / VC

8 r f L

(29)

To guarantee the ±0.5% BATT voltage accuracy, the maximum BATT voltage ripple must not exceed 0.5% (e.g. 0.2%). The worst case occurs at the minimum battery voltage of the CC charge with the maximum input voltage.



For VSYS_MAX=6V, VCC_MIN=VTC=3V, L=2.2µH, fSW=600kHz, %2.0_ MAXBATTr , CBATT is 39µF.

Two pieces of 22µF ceramic with X7R dielectrics capacitor in parallel will suffice.

PCB Layout Guide

PCB layout is very important to meet specified noise, efficiency and stability requirements. The following design considerations can improve circuit performance:

1) Route the power stage adjacent to their grounds. Aim to minimize the high-side switching node (SW, inductor) trace lengths in the high-current paths.

Keep the switching node short and away from all small control signals, especially the feedback network.

Place the input capacitor as close as possible to the VIN and PGND pins. The local power input capacitors, connected from the SYS to PGND, must be placed as close as possible to the IC.

Place the output inductor close to the IC and connect the output capacitor between the inductor and PGND of the IC.

2) For high-current applications, the power pads for IN, SYS, SW, BATT and PGND should be connected to as many coppers planes on the board as possible. This improves thermal performance because the board conducts heat away from the IC.

3) The PCB should have a ground plane connected directly to the return of all components through vias (e.g., two vias per capacitor for power-stage capacitors, one via per capacitor for small-signal components). A star ground design approach is typically used to keep circuit block currents isolated (power-signal/control-signal), which reduces noise-coupling and ground-bounce issues. A single ground plane for this design gives good results.

4) Place ISET, OLIM and ILIM resistors very close to their respective IC pins.

Top Layer

Bottom Layer

Figure 15: PCB Layout Example – board size is 22x25mm

Design Example

Below is a design example following the application guidelines for the specifications:

Table 3: Design Example VIN 5V/500mA for USB,

5V/3A for Adapter Charge 3.7V / 2.5A

Discharge 5V / 2.1A fSW 600kHz

Figure 16 shows the detailed application schematic. The Typical Performance Characteristics section shows the typical performance and circuit waveforms. For more possible applications of this device, please refer to the related Evaluation Board datasheets.



TYPICAL APPLICATION CIRCUITS

Figure 16: Typical Application Circuit of MP2637 with USB connectors



PACKAGE INFORMATION QFN-24 (4mmx4mm)


NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications.


Revision History

Revision # Revision

Date Description

Pages Updated

1.0 7/2/2014 Initial Release -

1.05 11/6/2020 Add a description to the feature list: IEC 62368-1 AK Certification

Page 1

mp2637 - monolithic power

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